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Topic: ST1200HD question
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Chip Gelmini
Phenomenal Film Handler
Posts: 1733
From: Brooksville, FL
Registered: Jun 2003
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posted May 22, 2007 04:54 PM
In theory, of course............
With 35mm projectors, there is usually a way to adjust the shutter timing to reduce "ghosting." These simple fixes on theater machines is nothing more than a knurled knob with an indicator point. When the problem is severe, then access to the blade with more accurrate adjustment can be performed. On a theater machine (again 35mm) you advance the picture frame 1/2 way down on the movement stroke (i.e. film claw to the 4 perf movie frame). On the Century "C" and "J" line of machines, a knotch on one blade of the shutter was aligned to a indicator point inside the sight glass of the picture head.
"Ghosting" - is when the shutter is not fully closed as the picture frame advances at the rate of 18 or 24FPS. Because the light is exposed and the film is advancing, the movement of the still frame is streaking. Bright street lamps for example, would appear to have alittle of that light directly above them. Sort of a trick to the eye vision - such as perfectly round circles (such as lab cues in the upper right hand corner) are naturally round but when projected with scope lenses they are vertically egg shaped.
Only when the shutter is 100% open at precisely the same time that the frame of film is 100% frozen in time will you not have ghosting.
As I said in theory this might have been a prototype adjustable shutter blade in your ST1200 and if I am right about this I would say this is a marvelous thing they put in to such a great machine.
But I would speculate here and please DO NOT go try to adjust it especially when this kind of thing represents shutter blocking light while the frame advances. In this manner adjusting this would NOT repeat NOT pick up the speed of your machine. If slower speed is a problem, then you need to address why it is running slow.
I would assume that (1) kevin Faulkner could address the reasons of your shutter blade in the ST1200HD; and that (2) Brad Miller could enlighten all of us alittle more on Ghosting but I do feel I have part of that right in the explanation.
Regards,
Chip G
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just curious why one had it and not the other arethere date codes on these machines to tell when they were manufactured?
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